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Question
Find the radius of curvature of the convex surface of a plano-convex lens, whose focal length is 0.3 m and the refractive index of the material of the lens is 1.5.
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Solution
The focal length of a combined lens can be determined by the formula
`1/f =(mu -1)(1/R_1 - 1/R_2)`
Here, R_2 =∞ and f =0.3m
`1/0.3 =( mu-1) xx 1/R_1`
`R_1 = 0.3(mu-1)`
`=0.3(1.5 -1)`
` =0.3 xx 0.5`
`= 0.15m`
`=15 cm`
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